Voltage supply circuitry and integrated circuit therefor

ABSTRACT

A voltage supply circuitry is capable of coupling to wired audio headset circuitry and configurable to operate in a first mode, wherein the voltage supply circuitry provides a voltage supply to the wired audio headset functionality circuitry. The voltage supply circuitry is further capable of coupling to visual indication circuitry and further configurable to operate in a second mode, wherein the voltage supply circuitry provides a voltage supply to the visual indication circuitry.

FIELD OF THE INVENTION

The field of the invention relates to voltage supply circuitry, and moreparticularly to provision of a voltage supply for a wired audio headsetand a visual indication of wireless headset functionality.

BACKGROUND OF THE INVENTION

In the field of mobile telecommunications, it is known for mobilecommunication units, such as mobile telephone handsets, to providepersonal hands-free functionality in, say, a form of an audio headset.Traditionally, an accessory such as an audio headset may be connected tothe mobile telephone handset via a wire, one end of which comprises, forexample, a jack that plugs into a socket provided by the mobiletelephone handset. More recently, wireless audio headset accessorieshave become popular, in particular in a form of Bluetooth™ headsets.Consequently, current mobile telephone handsets are required to providewired and wireless audio headset capabilities. Furthermore, suchhandsets are required to provide wired and wireless audio attachsignalling capabilities.

It has also become a commercial requisite for wireless (audio) attachfunctionality to comprise a visual indication of a status of wirelessfunctionality, typically in a form of a blue light emitting diode (LED),which requires a boosted positive voltage (namely a voltage greater thana voltage available from the handset battery source).

FIG. 1 illustrates an example of voltage supply circuitry for wiredaudio headset functionality 110 and for a visual indication 120 of astatus of wireless functionality, for example within a mobilecommunication unit, as is known in the art. Due to their respectivevoltage requirements, the wired audio headset functionality 110 and thevisual indication element 120 are each provided with a dedicated voltagesupply.

For the illustrated example, the voltage supply for the wired audioheadset functionality 110 comprises a voltage regulator 115, operativelycoupled to a 3.6 v voltage supply (V_(bat)) supplied from a batterysource (not shown). The voltage regulator 115 provides the wired audioheadset functionality 110 with a supply voltage (V_(audio)) of 2.8 v.The wired audio headset functionality 110 provides two audio outputs fora headset coupled thereto. Each output is coupled to a headset via acoupling capacitor 117 to remove a DC (direct current) offset.Typically, wired audio headset functionality requires a positive voltagesupply and a negative voltage supply for a capacitor-less coupled audioamplifier implementation.

The voltage supply for the visual indication element 120 of a wirelessoperation comprises Boost or Charge Pump circuitry 125, which is alsocoupled to the voltage supply (V_(bat)) from the battery. TheBoost/Charge Pump circuitry 125 provides the visual indication element120 with a boost voltage (V_(boost)) of, say, 5.5 v. The boost voltage(V_(boost)) is provided to the visual indication element 120, which isalso coupled to a driver circuit 127.

The voltage supply circuitry for wired audio headset functionality 110and for visual indication element 120 of a wireless operation may beprovided on a semiconductor device 130, such as an integrated circuit.Also illustrated is DC/DC converter circuitry 140, arranged to provide a1.8 v voltage supply (V_(mem)) to, for example, memory components, orother components of the mobile communication unit. As will beappreciated, the provision of a dedicated voltage supply for each of thewired audio headset functionality 110 and for the visual indicationelement 120 of the status of wireless functionality is consuming interms of silicon area, and is also expensive in terms of componentcount.

As more sophisticated functionality permeates its way down to lower tiermobile telephone handsets, the need to provide such functionality,whilst keeping the size and cost of the handset as low as possible,increases. Thus, a need exists for an improved voltage supply circuitryfor wired audio headset functionality circuitry that is also able tosupport visual indication circuitry for wireless (headset) attachsignalling functionality, for example within a mobile communicationunit.

SUMMARY OF THE INVENTION

In accordance with aspects of the invention, there is provided a voltagesupply circuitry and a semiconductor device comprising at least part ofa voltage supply circuitry as defined in the appended Claims.

Specific embodiments of the invention as set forth in the dependentclaims. Further details and aspects will be described, by way of exampleonly, with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of known voltage supply circuitry.

FIG. 2 illustrates voltage supply circuitry in accordance with anembodiment of the invention.

FIG. 3 illustrates an example of voltage supply circuitry according toan embodiment of the invention.

FIG. 4 illustrates the voltage supply circuitry of FIG. 3 in a firststate.

FIG. 5 illustrates the voltage supply circuitry of FIG. 3 in a secondstate.

FIG. 6 illustrates the voltage supply circuitry of FIG. 3 in a thirdstate.

DESCRIPTION OF EMBODIMENTS

Embodiments of the invention will now be described in terms of a mobilecommunication unit arranged to provide wired and wireless (audioheadset) attach signalling capabilities. Although embodiments of theinvention will be described in terms of a mobile communication unit, itwill be appreciated that the inventive concept herein described may beembodied in any apparatus that incorporates wired and wireless audioheadset capabilities.

A voltage supply circuitry may be arranged to be coupled to wired audioheadset circuitry and configurable to operate in a first mode, whereinthe voltage supply circuitry provides a voltage supply to the wiredaudio headset circuitry. The voltage supply circuitry may be furtherarranged to be coupled to visual indication circuitry and furtherconfigurable to operate in a second mode, wherein the same voltagesupply circuitry provides a voltage supply to the visual indicationcircuitry.

Referring now to FIG. 2, there is illustrated a configurable voltagesupply circuitry 200 in accordance with an embodiment of the invention.The configurable voltage supply circuitry 200 is coupled to a voltagesource, which for the illustrated embodiment takes the form of V_(bat),provided by a battery source (not shown) of, for example, a mobilecommunication unit of which the configurable voltage supply circuitry200 forms a part. The configurable voltage supply circuitry 200 iscoupled to wired audio headset circuitry 210 and visual indicationcircuitry 220. The visual indication circuitry 220 comprises a visualindication element 230 operably coupled to driver circuitry 240, andprovides an indication of a status of wireless (headset) attachfunctionality (not shown) of the mobile communication unit.

Also illustrated in FIG. 2 is a DC/DC converter 250, which convertsV_(bat) to a voltage supply (V_(mem)) for other components (not shown)such as memory elements and the like. For the illustrated embodiment,for the purpose of power efficiency of the system, wired audio headsetcircuitry 210 is further coupled to, and receives as a positive voltagesupply, V_(mem). Configurable voltage supply circuitry 200 is alsocoupled to V_(mem).

The configurable voltage supply circuitry 200 may be configurable tooperate in a first mode, wherein the voltage supply circuitry provides avoltage supply to the wired audio headset circuitry 210. For theillustrated embodiment, the configurable voltage supply circuitry 200,when operating in the first mode, provides the wired audio headsetcircuitry 210 with a negative voltage supply, substantially equal andopposite to the positive voltage supply V_(mem). Thus, for theillustrated embodiment, the wired audio headset circuitry 210 receives apositive voltage supply, e.g. of 1.8V, from the DC/DC converter 250, anda negative voltage supply, e.g. of −1.8V, from the configurable voltagesupply circuitry 200, when the configurable voltage supply circuitry 200is configured to operate in the first mode.

The configurable voltage supply circuitry 200 is further configurable tooperate in a second mode, wherein the configurable voltage supplycircuitry 200 provides a voltage supply to the visual indicationcircuitry 220. Thus, the first mode and second mode are mutuallyexclusive modes of operation, in that only one of the first mode orsecond mode may be operational at any point in time.

For the illustrated embodiment, the visual indication element 230 is ina form of a light emitting diode (LED). As will be appreciated by askilled artisan, visual indications of a status of wireless (headset)attach functionality for mobile communication units, for example mobiletelephone handsets, typically comprise blue light emitting elements.Consequently, the visual indication circuitry 200 may comprise a blueLED. As will also be appreciated by a skilled artisan, typically blueLEDs require a voltage greater than that provided by a battery sourcefrom within a mobile communication unit. For example, to operate, a blueLED may require a voltage greater than approximately 4.2V, whilst abattery source within a mobile communication unit may provide a voltageof approximately only 3.6V. Accordingly, for the illustrated embodiment,the voltage supply circuitry 200, when operating in the second mode, isconfigured to provide a boosted voltage supply to the visual indicationcircuitry 220.

The ability of the configurable voltage supply circuitry 200 to beconfigured to operate in either of two modes, a first mode in which theconfigurable voltage supply circuitry 200 provides a voltage supply tothe wired audio headset circuitry 210 and a second mode in which theconfigurable voltage supply circuitry 200 provides a voltage supply tothe visual indication circuitry 220, substantially alleviates theproblem of having to provide a dedicated voltage supply for each of thewired audio headset circuitry 210 and the visual indication circuitry220. In this manner, a cost of providing a voltage supply to the wiredaudio headset circuitry and the visual indication circuitry, in terms ofcomponent count and silicon area, may be significantly reduced.

As will be appreciated by a skilled artisan, since the use of wiredaudio headset circuitry and wireless (headset) attach functionality tendto be mutually exclusive, the provision of common voltage supplycircuitry for both the wired audio headset circuitry and the visualindication circuitry for the wireless (headset) attach functionality isunlikely to result in a conflict between the voltage supply demands ofthe two functionalities.

As previously mentioned, for the embodiment illustrated in FIG. 2, theconfigurable voltage supply circuitry 200, when configured to operate inthe first mode, provides the wired audio headset circuitry 210 with anegative voltage supply, substantially equal and opposite to thepositive voltage supply V_(mem), that is also provided to the wiredaudio headset circuitry 210 by the DC/DC converter 250. As will beappreciated by a skilled artisan, by using these two opposing voltagesupplies for amplifying audio signals provided to an audio headset 260connected thereto, the resulting audio signals would comprisesubstantially no DC (offset) component, making these resulting audiosignals ground referred. Accordingly, and as illustrated in FIG. 2, theaudio headset 260 may be coupled to the audio headset circuitry 210without a need for coupling capacitors, further enabling a reduction inthe cost of the wired audio headset circuitry, in terms of componentcount and silicon area.

Furthermore, it is envisaged that the configurable voltage supplycircuitry 200 may form part of a semiconductor device, such asintegrated circuitry (IC) 270. It is further envisaged that theconfigurable voltage supply circuitry 200 may form a part of asemiconductor device comprising the wired audio headset functionalityand the visual indication circuitry.

Referring now to FIG. 3, there is illustrated an example of aconfigurable voltage supply circuitry 200 according to an embodiment ofthe invention. For the illustrated embodiment, the configurable voltagesupply circuitry 200 comprises a charge storage device, in a form of acapacitor 310, and a plurality of switching elements, referenced P1, P2and P3.

Referring now to FIG. 4, there is illustrated the configurable voltagesupply circuitry 200 of FIG. 3 in a first state. In this first state,two of the switching elements, referenced P1, are configured in a closedcondition, whilst switching elements P2 and P3 are configured in an opencondition. In this manner, a first connection of the capacitor 310 iscoupled to V_(in), which as illustrated in FIG. 2 is, in turn, coupledto the output of the DC/DC converter, and as such provides 1.8 volts toa first connection of the capacitor 310. A second connection of thecapacitor 310 is coupled to ground. Accordingly, the capacitor ischarged to a potential difference of 1.8V.

Referring now to FIG. 5, there is illustrated the voltage supplycircuitry 200 of FIG. 3 in a second state. In this second state,switching elements P1 are opened, following the first state illustratedin FIG. 4, whilst switching elements P2 are closed. Switching elementsP3 remain open. In this manner, the first connection of the capacitor310 is decoupled from V_(in), and coupled to ground. Conversely, thesecond connection of the capacitor 310 is decoupled from ground, andcoupled to V_(out). In this manner, due to a potential difference of 1.8v across the capacitor 310, this reversal of polarity of the capacitorresults in a negative voltage of −1.8V at V_(out).

Thus, by initially placing the configurable voltage supply circuitry 200into the first state, illustrated in FIG. 4, whereby the capacitor ischarged to a positive voltage of 1.8V, and subsequently placing theconfigurable voltage supply circuitry 200 into the second state,illustrated in FIG. 5, whereby the polarity of the capacitor is reversedto create a negative voltage, the configurable voltage supply circuitry200 may be configured to provide a negative voltage supply of −1.8V tothe wired audio headset circuitry 210.

In order to maintain the −1.8 v at V_(out), the voltage supply circuitry200 is alternated between the first and second states, enabling thecapacitor 310 to be re-charged. A second, output capacitor (C_(out)) 510is operably coupled to V_(out), such that when the voltage supplycircuitry 200 is in the second state, the output capacitor 510 issubstantially charged to −1.8 v, and which substantially maintains the−1.8 v at V_(out) whilst the supply circuitry alternates to the firststate.

Referring now to FIG. 6, there is illustrated the configurable voltagesupply circuitry 200 of FIG. 3 in a third state. In this third state,switching elements P1 are opened, following the first state illustratedin FIG. 4, whilst switching elements P3 are closed. Switching elementsP2 remain open. In this manner, the first connection of the capacitor310 is decoupled from V_(in), and coupled to V_(out). Conversely, thesecond connection of the capacitor 310 is decoupled from ground, andcoupled to V_(bat). In this manner, due to the potential difference of1.8V across the capacitor 310, the voltage provided by Vbat is boostedfrom 3.6V (for the illustrated embodiment) to 5.4V.

Thus, by initially putting the voltage supply circuit 200 into the firststate, illustrated in FIG. 4, whereby the capacitor is charged to 1.8 v,and subsequently putting the voltage supply circuit 200 into the thirdstate, illustrated in FIG. 6, whereby the voltage provided by V_(bat) isboosted to 5.4V by the voltage across the capacitor, the voltage supplycircuitry 200 may be configured to provide a voltage supply of 5.4V tothe visual indication circuitry 220.

In order to maintain the 5.4V at V_(out), the voltage supply circuitry200 is alternated between the first and third states, thereby enablingthe capacitor 310 to be re-charged. When the voltage supply circuitry200 is in the third state, the output capacitor 510 is substantiallycharged to 5.4V, and which substantially maintains the 5.4V at V_(out)whilst the supply circuitry alternates to the first state.

It is envisaged that the switching elements P1, P2, P3 may comprisetransistors or the like, and may be controlled by, and as such theconfigurable voltage supply circuitry may be configured by, a centralprocessing unit (not shown) of the mobile communication unit. Forexample, the mobile communication unit may comprise logic or softwarearranged to control audio headset operation. In this manner, the centralprocessing unit may be arranged to control wired audio headset circuitryand visual indicator circuitry for indicating a status of wireless(headset) attach functionality, and to configure the voltage supplycircuitry in accordance with audio headset requirements.

It is within the contemplation of the invention that at least a part ofthe configurable voltage supply circuitry may be provided within asemiconductor device, such as an integrated circuit (IC) package, and inparticular may be provided within a semiconductor device comprising acentral processing unit. Alternatively, it is envisaged that a part ofthe configurable voltage supply circuitry, for example the switchingelements P1, P2, P3 may be provided within a semiconductor device,whilst the charge storage device may be provided external to thesemiconductor device, for example mounted on a printed circuit board onwhich the semiconductor device is also mounted. In this manner, theproperties of the charge storage device, for example the capacitivevalue of the charge storage device, may be varied depending on thespecific requirements of different applications.

It will be understood that the configurable voltage supply circuitry, asdescribed above, aims to provide at least one or more of the followingadvantages:

-   -   (i) A provision of common voltage supply circuitry for wired        audio headset circuitry and the visual indication circuitry for        wireless (headset) attach functionality.    -   (ii) Reduced cost of providing a voltage supply to wired audio        headset circuitry and visual indication circuitry, in terms of        component count and silicon area.    -   (iii) Coupling of wired audio headset to audio headset circuitry        without a need for coupling capacitors    -   (iv) The inventive concept is backward compatible to legacy        audio headset accessories, such as a stereo headset (using a        jack) and a Bluetooth (ear-piece) accessory.

In particular, it is envisaged that the aforementioned inventive conceptcan be applied by a semiconductor manufacturer to any integrated circuitarchitecture supporting an improved voltage supply circuitry for wiredaudio headset circuitry and visual indication circuitry for a wireless(headset) attach functionality. It is further envisaged that, forexample, a semiconductor manufacturer may employ the inventive conceptin a design of a stand-alone device, or application-specific integratedcircuit (ASIC) and/or any other sub-system element employing anintegrated circuit to support an improved voltage supply circuitry forwired audio headset functionality circuitry and visual indicationcircuitry for the wireless (headset) attach functionality.

It will be appreciated that any suitable distribution of functionalitybetween different functional units or logic or switching elements, maybe used without detracting from the inventive concept herein described.Hence, references to specific functional devices or elements are only tobe seen as references to suitable means for providing the describedfunctionality, rather than indicative of a strict logical or physicalstructure or organization.

It is envisaged that aspects of the invention may be implemented in anysuitable form including hardware, software, firmware or any combinationof these. The elements and components of an embodiment of the inventionmay be physically, functionally and logically implemented in anysuitable way. Indeed, the functionality may be implemented in a singleunit or IC, in a plurality of units or ICs or as part of otherfunctional units.

Although the present invention has been described in connection withsome embodiments, it is not intended to be limited to the specific formset forth herein. Rather, the scope of the present invention is limitedonly by the accompanying claims. Additionally, although a feature mayappear to be described in connection with particular embodiments, oneskilled in the art would recognize that various features of thedescribed embodiments may be combined in accordance with the invention.In the claims, the term ‘comprising’ does not exclude the presence ofother elements or steps.

Furthermore, although individual features may be included in differentclaims, these may possibly be advantageously combined, and the inclusionin different claims does not imply that a combination of features is notfeasible and/or advantageous. Also, the inclusion of a feature in onecategory of claims does not imply a limitation to this category, butrather indicates that the feature is equally applicable to other claimcategories, as appropriate.

Furthermore, the order of features in the claims does not imply anyspecific order in which the features must be performed and in particularthe order of individual steps in a method claim does not imply that thesteps must be performed in this order. Rather, the steps may beperformed in any suitable order. In addition, singular references do notexclude a plurality. Thus, references to ‘a’, ‘an’, ‘first’, ‘second’etc. do not preclude a plurality.

Thus, an improved voltage supply circuitry for wired audio headsetcircuitry and visual indication circuitry for wireless headsetfunctionality has been described, where the aforementioned disadvantageswith prior art arrangements have been substantially alleviated.

The invention claimed is:
 1. A device comprising: a voltage supplycircuitry comprising an output coupled to a wired audio headsetamplifier and coupled to visual indication circuitry: in a firstoperational mode the voltage supply circuitry is to provide a negativevoltage with respect to a reference voltage to the wired audio headsetamplifier via the output; and in a second operational mode the voltagesupply circuitry is to provide a positive voltage with respect to thereference voltage to the visual indication circuitry via the output. 2.The voltage supply circuitry of claim 1 wherein the negative voltage isequal to and opposite to a positive voltage supplied to the wired audioheadset amplifier.
 3. The voltage supply circuitry of claim 2 whereinthe voltage supply circuitry provides a boosted voltage supply to thevisual indication circuitry, when operating in the second mode.
 4. Thevoltage supply circuitry of claim 1 wherein the voltage supply circuitryprovides a boosted voltage supply to the visual indication circuitrywhen operating in the second mode.
 5. The voltage supply circuitry ofclaim 1 further characterised in that the first operational mode andsecond mode are mutually exclusive modes of operation, wherein: thefirst operational mode involves a first setting of switches of thevoltage supply circuitry; the second operational mode involves a secondsetting of the switches; and no setting of the switches enables thevoltage supply circuitry to simultaneously provide negative voltage tothe wired audio headset amplifier and provide positive voltage to thevisual indication circuitry.
 6. The voltage supply circuitry of claim 1wherein the voltage supply circuitry provides a negative voltage to thewired audio headset amplifier by placing the voltage supply circuitryinto a first state, whereby a charge storage device is charged to apositive voltage, and subsequently placing the voltage supply circuitryinto a second state, whereby the polarity of the charge storage deviceis reversed to create a negative voltage.
 7. The voltage supplycircuitry of claim 6 wherein the voltage supply circuitry provides aboosted voltage supply to the visual indication circuitry by placing thevoltage supply circuitry into the first state, and subsequently placingthe voltage supply circuitry into a third state, whereby a voltageprovided by a battery source is boosted by voltage of the charge storagedevice.
 8. The voltage supply circuitry of claim 7 wherein the chargestorage device comprises a capacitor.
 9. The device of claim 1 wherein:in the first operational mode the voltage supply circuitry does notprovide the positive voltage with respect to the reference voltage tothe visual indication circuitry; and in the second operational mode thevoltage supply circuitry does not provide the negative voltage withrespect to the reference voltage to the wired audio headset amplifier.10. A semiconductor device comprising: voltage supply circuitry capableof coupling to a wired audio headset amplifier and having a firstoperational mode in which a charge storage device of the voltage supplycircuitry provides a negative voltage with respect to a referencevoltage to the wired audio headset amplifier under a first configurationof switches of the voltage supply circuitry; wherein the voltage supplycircuit is further capable of coupling to visual indication circuitryand having a second operational mode in which the charge storage deviceprovides a positive voltage with respect to the reference voltage to thevisual indication circuitry under a second configuration of theswitches; and wherein the charge storage device does not include a firstcomponent and a second component wherein: the first component and thesecond component are charge storage devices; the first componentprovides the negative voltage with respect to the reference voltage tothe wired audio headset amplifier under the first configuration ofswitches of the voltage supply circuitry; and the second componentprovides the positive voltage with respect to the reference voltage tothe visual indication circuitry under the second configuration of theswitches.
 11. The semiconductor device of claim 10 wherein the negativevoltage is equal and opposite to a positive voltage supplied to thewired audio headset amplifier.
 12. The semiconductor device of claim 10wherein the voltage supply circuitry provides in the first operationalmode a negative voltage to the wired audio headset circuitry by placingthe voltage supply circuitry into a first state, whereby a chargestorage device is charged to a positive voltage, and subsequentlyplacing the voltage supply circuitry into a second state, whereby thepolarity of the charge storage device is reversed to create a negativevoltage.
 13. The semiconductor device of claim 10 wherein the voltagesupply circuitry is arranged to provide a boosted voltage supply to thevisual indication circuitry by placing the voltage supply circuitry intoa first state, whereby a charge storage device is charged to a positivevoltage, and subsequently placing the voltage supply circuitry into athird state, whereby a voltage provided by a battery source is boostedby the voltage of the charge storage device.
 14. The semiconductordevice of claim 11 wherein the voltage supply circuitry provides in thefirst operational mode a negative voltage to the wired audio headsetcircuitry by placing the voltage supply circuitry into a first state,whereby a charge storage device is charged to a positive voltage, andsubsequently placing the voltage supply circuitry into a second state,whereby the polarity of the charge storage device is reversed to createa negative voltage.
 15. The semiconductor device of claim 14 wherein thevoltage supply circuitry is arranged to provide a boosted voltage supplyto the visual indication circuitry by placing the voltage supplycircuitry into the first state and subsequently placing the voltagesupply circuitry into a third state, whereby a voltage provided by abattery source is boosted by voltage of the charge storage device. 16.The semiconductor device of claim 12 wherein the voltage supplycircuitry is arranged to provide a boosted voltage supply to the visualindication circuitry by placing the voltage supply circuitry into thefirst state and subsequently placing the voltage supply circuitry into athird state, whereby a voltage provided by a battery source is boostedby voltage of the charge storage device.
 17. The semiconductor device ofclaim 10 wherein the voltage supply circuit is further capable ofcharging the charge storage device to a positive voltage under a thirdconfiguration of the switches.
 18. The semiconductor device of claim 17wherein the voltage supply circuit alternates between the firstconfiguration of the switches and the third configuration of theswitches to provide a negative voltage with respect to the referencevoltage to the wired audio headset amplifier and to charge the storagedevice.
 19. The semiconductor device of claim 17 wherein the voltagesupply circuit alternates between the second configuration of theswitches and the third configuration of the switches to provide aboosted voltage supply to the visual indication circuitry and to chargethe storage device.
 20. A method comprising: providing by voltage supplycircuitry during a first operational mode a negative voltage withrespect to a reference voltage to a wired audio headset amplifier via anoutput; and providing by the voltage supply circuitry during a secondoperational mode a positive voltage with respect to the referencevoltage to visual indication circuitry via the output, wherein: theoutput is coupled to the wired audio headset amplifier and to the visualindication circuitry; and the first operational mode and the secondoperational mode do not coincide.